White horses of the Camargue thunder through the shallow salt flats at sunset on December 8, 2022. Known as Horses of the Sea, the breed native to the wetlands in southern France is one of the oldest in the world. (Photo by Nathalie Mountain/Media Drum Images)

[

Lake Natron is a salt lake located in northern Tanzania, close to the Kenyan border, in the eastern branch of the East African Rift. The lake is fed by the Southern Ewaso Ng'iro River and also by mineral-rich hot springs. It is quite shallow, less than three meters (10 feet) deep, and varies in width depending on its water level, which changes due to high levels of evaporation, leaving concentrations of salt and other minerals, notably sodium carbonate (natron).

In this June 29, 2018 photo, a wild horse shakes off dust near a watering hole outside Salt Lake City. Harsh drought conditions in parts of the American West are pushing wild horses to the brink and forcing extreme measures to protect them. (Photo by Rick Bowmer/AP Photo)

A man salts a downtown sidewalk in Washington, Thursday, March 5, 2015, as snow begins to fall. The U.S. federal government said its offices in the Washington area will be closed Thursday because of a new round of winter weather expected in the region. The Office of Personnel Management said non-emergency personnel in and around Washington were granted excused absences for the day. Emergency employees and telework-ready employees were expected to work. (AP Photo/Andrew Harnik)

A dead sperm whale is seen on the beach on March 18, 2012 in Yancheng, Jiangsu Province of China. Four giant sperm whales, which were found beached on the beach of Xintan Salt Field on Friday, died on Saturday despite rescue efforts. (Photo by ChinaFotoPress)

A woman hangs strips of salted meat she collected from different places during the Muslim's Eid al-Adha or Festival of Sacrifice, in Lahore, Pakistan, Sunday, August 2, 2020. Pakistanis are celebrating the Eid al-Adha, or the Feast of the Sacrifice, to mark the willingness of the Prophet Ibrahim – Abraham to Christians and Jews – to sacrifice his son. During the holiday Muslims slaughter sheep and cattle, distribute part of the meat to the poor. (Photo by K.M. Chaudary/AP Photo)

A monolith placed in the Utah wilderness in November 2020. New clues have surfaced in the disappearance of the gleaming monolith that seemed to melt away as mysteriously as it appeared in the red-rock desert. A Colorado photographer told a TV station in Salt Lake City that he saw four men push over the hollow, stainless steel structure last Friday night. (Photo by Terrance Siemon/AP Photo)

A cenote is a natural phenomenon, a sinkhole in the Earth’s surface. The Yucatan Peninsula in Mexico has an estimated 7,000 cenotes because it is primarily made up of porous limestone. For millions of years, rainfall slowly ate away at the limestone and a huge system of underground caves and caverns was formed. Many filled with water from rain or from the underground water table. When the roof of a water filled cave collapses, a cenote is born. The water found in a cenote may be fresh water, salt water, or both. Structurally it may be completely open, like a lake, almost completely closed with just a small opening at the top, or somewhere in between.